Plectranthus argentatus Silver Spurflower

Cultural Codes

Some of you grow only indoors, some only in terrariums; many of you have hobby greenhouses; while a growing number of customers live in subtropical or tropical areas of the world. These brief codes are an attempt to suggest whether or not a particular plant will do well in your particular conditions.

• HP - House Plant, performing adequately in the ordinary home
• CGH - Cool Greenhouse, for ideal growing conditions; most low temperature plant rooms would also fall within this code
• TGH - Tropical Greenhouse, for plants needing constant warmth and higher humidity; also would describe growth chamber setup some of you have built in your basements
• TERR - Terrarium culture is most successful or appropriate
• HT - Hardy Temperate: winder hardy at least to Zone 7 or to Zone 6
• HH - Half Hardy, possibly damaged in a prolonged winter, but reliable outdoors in Zone 8
• HB - Hardy Bulb
• SSA - Self Sowing Annual
• y - indicates a plant or groundcover popular in bonsai work
• h - indicates a bog plant, or an aquatic
• v - indicates a plant appropriate for terrariums

If an entry has the cluster HP CGH, this means normal house plant culture will be successful if the plant is given a cool CGH moist location; however if the entry has the cluster CGH HP, you would interpret this to suggest that while Cool Greenhouse conditions are needed for total success with this plant, House Plant conditions will be adequate, while not ideal. If the cluster is HH CGH you would interpret this to mean that while in Zone 8 or below this will be winter hardy outdoor, further north it will need considerable mulch, a cold frame, or a Cool Greenhouse to thrive. And so on.